Fluid circulation system



May. 15, 1962 nB. J. soBoL 3,034,505

FLUID CIRCULATION SYSTEM Filed Feb. 24, 1959 2 sheets-sheet 1 33 Us INVENTOR.

ATTORNEY United States Patent 3,034,505 FLUID CIRCULATION SYSTEM Bruce J. Sobol, White Plains, N.Y. (6 Robins Roost, Port Chester, N.Y.) Filed Feb. 24, 1959, Ser. No. 795,145 4 Claims. (Cl. 12S-214) This invention relates to extracorporeal circulation devices and, more particularly, to an improved unit for oxygenating venous blood.

Itis now generally recognized that operative procedures upon the heart and its associated vessels can be better performed when the heart is temporarily relieved of its function of pumping blood. Relieving the heart of its normal function, even if for only a short period of time, relieves many of the attendant surgical operative difficulties. However, in order to maintain life during a ternporary cessation of blood ilow for anappreciable time, it becomes necessary to assume kthe cardiorespiratory functions of the subject by some other means during the interval in which the heart is relieved.

The introduction of oxygen into venous blood in a mechanical device adapted to provide a functional replacement for the lungs is a problem beset by many difiiculties. In order to introduce adequate and predetermined amounts of oxygen into venous blood, in accordance with the present invention, it has been found desirable to provide a large surface -area for oxygenating purposes and to manipulate the blood thereon in such a manner as to form a continuous thin film of blood of controllable surface area. This provides high oxygenation efficiency and yet utilizes only a small volume of blood at any given instant passing throughthe oxygenating atmosphere at a relatively high iiow rate without any detrimental foaming or bubbling of the blood in its passage through the unit. Rivulet How of blood over the oxygenating surfaces greatly reduces the available blood surface area and thus reduces the oxygenation efficiency to negligible amounts.

It is, therefore, an object of the present invention to provide an eXt-racorporeal circulation device for oxygenating venous blood over a relatively large surface are-a so as to substantially increase the oxygenating efficiency of the unit with no foaming or bubbling thereof and detrimental hemolysis resulting from trauma in passage through the unit.

Another object of the present invention is to provide a venous blood oxygenating unit of the type described having two completely closed fluid flow systems for circulating blood and oxygen, respectively, therethrough, separated only by a liquid impervious but oxygen and CO2 transmitting membrane, whereby the blood will take up the oxygen and give up CO2 as it passes through its iluid flow system.

Still another object of the present invention is to provide an extracorporeal system for oxygenating blood, which may be conveniently converted for use as a dialyzing system for temporarily replacing all excretory functions of a kidney.

A more specific object of the present invention is to provide a membrane element particularly adapted for use in an extracorporeal circulation system.

All of the foregoing and still further objects yand advantages of this invention will become apparent from a study of the following specification, taken in connection with the accompanying drawing, wherein:

FIG. 1 is a diagrammatic perspective view of extracorporeal circulation apparatus made in accordance with the present invention in operative use.

FIG. 2 is an enlarged transverse cross-sectional view taken along line 2-2 of FIG. l.

3,034,505, Patented May 15, 1962 FIG. 3 is a longitudinal cross-sectional view Ytaken along line 3-3 of FIG. l. l

FIG. 4 is a fragmentary plan view of a membrane element forming a part of .the present invention.

FIG. 5 is a top plan view of a frame forming apart of the present invention.

FIG, 6 is a longitudinal Across-sectional view taken along line 6 6 of FIG. 5.

FIG, 7 is a bottom plan view of the frame shown in FIG. 5.

FIGS. 8 and 9 are transverse cross-sectional views taken along lines -8-8 and 9 9 of FIG. 5

FIG. l0 is a fragmentary perspective view of parts of the frame.

FIG. 11 is a fragmentary perspective View taken along line 11-11 of FIG. 10.

.Referring now more in detail to the drawing, and more particularly to FIGS. l to 3 thereof, an extracorporeal circulation system made in accordance with the present invention is shown to include a main iiuid ilow control unit 15 that is mainly constructed from a plurality of sets of panels secured together in predetermined relationship so as to define two separate uid flow paths, one of which is used to circulate body iluid, such as blood therethrough, while the other is used to circulate a body fluid purifying agent therethrough, such as oxygen.

In FIG. 2 of the drawing, each panel 20 is shownto include a pair of substantially identical frames 22a, b, each having a Vface side 23 and a back side 24, respectively, secured together with the face sides 23 thereof in facing relationship with eachother. These frames 22a, b are of substantially rectangular construction having .a pair of end strips, a pair of side strips, and a centrally positioned longitudinally extending cross piece 27, all of which define a pair of substantially identical rectiangular openings 26. The inner edges of the side strips and both edges of the cross piece 27 of one frame 2217 define one set of longitudinal channels 29, adjacent to each rectangular opening 26, that face the corresponding longitudinal channels 29 in the face side'23 of the associated frame 22a, so as to define longitudinally extending ducts therewith, for purposes hereinafter more fully described. As is particularly shown in FIG. 7 of the drawing, each such longitudinal channel 29 has an as sociated lip 30 that extends partly toward the corresponding lip 30 of the associated frame for restricting the opening erebetween. The back side 24 of each of the frames 22a, b has a pair of transverse channels 31,

each along the inside edge of the endstrips Ithereof.

A layer 33a, b of suitable material such as polyethylene is secured to the face side 23 of each frame 22a, b and ismade to conform to the irregular surface 'conigurationsurface configuration of the face side 23 of the frames- 22a, b, the passageways 36 communicate directly at one.

end Iwith the enlarged inner longitudinal conduits 3-8 extending through the facing longitudinal channels 29 along each edge of the crosspieces 27 of the facing frames 22a,l

b, and at the opposite end with similar conduits 42. along the inside edges off the side strips. The edges of the layers 33a, b adjacent to the end strips of the frames 22a,

b are tightly sealed together so as to prevent communication with the interior of the membrane element 35 through the ends, thus restricting ow within the compositemern- D brane 35 in a transverse direction from one conduit 38 to the other 42 at the opposite ends of each rectangular opening 26.

Each assembled panel 20 has a central bore 40 extending vthrough the center of the cross-pieces 27, such bore being of suciently large diameter to communicate with the longitudinal conduits 42 on both sides of the crosspiece 27, thus providing communication between the inteors of both membrane elements carriedby each panel. Likewise, a bore 43a, b extends through each side piece of the panel and is so positioned as to communicate with the transverse conduits 42 adjacentto the inner edges of the side pieces. Thus, with a plurality of panels 20 secured together in stacked relationship, the bores 49 deiine'a single continuous duct through which a body fluid, such as blood may be directed, such fluid finding its way into the conduits 38 on both sides of the cross-pieces 27 `and into the passageways 36 of all of the membrane elements 35, flowing throuch such membrane elements into the longitudinal conduits 42 adjacent to the inner edges of the side pieces, and through the bores 43a, b that form a pair of continuous ducts for the return flow of a body duid outwardly from the extracorporeal circulation system. The aforementioned fluid inlet duct 40, longitudinal conduits 38, 42, pasageways 36 vthrough the membrane elements 35, and outlet ducts 43a, b thus constitute a first lluid flow system lfor circulating therethrough the body fluid to be puried.

A second fluid flow system for circulating a body duid agent, such as oxygen, is provided by the transverse channels 31 in the back sides 24 of each yframe 22a, b, which channels of adjacent frames are in facing relationship with each other, and thus communicate with the space between adjacent membrane elements 35. Each side piece f the frames 22a, b is provided with a bore 45, 47 that communicates with the longitudinal channels 31, thus dening continuous ducts communicating with the space between each pair of membrane elements 35. A s a result, a fluid purifying agent, such as oxygen supplied to one of the ducts 45, designated an inlet duct, will pass through all of the spaces between the adjacent membrane elements 35 and outwardly through the other such duct 47, designated an outlet duct. As a result, the ducts 45, 47 and communicating transverse channels 31 on the yfacing back sides 24 of the frames 22a, b of all of the assembled panels define the second fluid flow system for purposes hereinafter more fully described.

In assembling the unit `for use, a selected number of complete panels 20 are secured together in stacked relationship, as shown in FIGS. 1 to 3. Central 'bosses 27a on each crosspiece 27 serve to support the central portions of the panels. A base plate 50 completely seals off all of the aligned ducts 40, 43a, b, 45 and 47, while a top plate 52 provided with fittings aligned with such ducts 40, 43a, b, 45, and 47 completely seeals oi the spacci above the membrane element 35 of the uppermost panel 20. A fitting 54 above the upper end of the body uid inlet duct 40 provides means for connecting one end of a exible tube 55 thereto which may have a fluid extracting device such `as a catheter at the opposite end `for receiving body huid from the subject. Such body fluid may be withdrawn at a selected rate to provide for the proper circulation of the body -iiuid through the extracorporeal circulation system. Other ttings 60a, b communicating with the outlet ducts 43a, b provide means for connecting one end of -a pair of flexible tubes 61a, b thereto that may be used -to return the body uid to the subject, such as by needles. Another fitting 64 communicating with one of the ducts 45, 47 of Ithe second uid ilow path is used to connect the supply conduit 65 that delivers the fluid purifying agent, such as from a supply tank 66 of oxygen. A vent is provided by another fitting 68 that communicates With'the other one of the ducts 45, 47 yand serves to exhaust the oxygen supplied to the system by the inlet coupling 64.

The operation of this device will now be more clearly understood. With the system connected in the manner illustrated in FIG. 1 of the drawing, for the purpose of oxygenating the blood Aof the patient, a catheter is used to withdraw such blood from the patient and to feed it to the blood inlet coupling 54 and duct 40. The blood is thus delivered to all of the communicating longitudinal conduits 38 along the opposite edges of the aligned crosspiecesr27, yfrom which it flows outwardly in opposite directions through the tortuous passageways 36 between the layers 33a, b of each membrane element 35. When used as an oxygenating system, such layers 33a, b are preferably constructed from a liquid-impervious 'and gas-transmitting plastic sheeting, such as polyethylene. Upon reaching the outer longitudinal conduits 42 adjacent to the inner edges of the side pieces of the panels, the blood is directed into the outlet ducts 43a, b from which it is withdrawn through the connecting tubes 61a, b and returned to the arterial system of the subject. Simultaneously, with the aforementioned flow of blood through the iirst duid flow system, oxygen is circulated through the second fluid flow system of the device. Such oxygen entering the inlet duct 45, flows through all of the communicating transverse channels 31 and through the space between `adjacent ones of the membrane elements 35 to the opposite side thereof, from which it escapes through the outlet duct and vent fitting 68.

It will now be recognized that the large number of small seals 34 in each membrane provide for constricted passageways through the layers 33a, b of each membrane element 35, which passageways serve as tiny channels or capillaries. As blood is forced through these capillaries, and as oxygen is passed over the outer surfaces of such composite membranes 35, the blood will take up the oxygen through the gaseous transmitting layers 33a, b without the blood owing outwardly from such passageways through the liquid impervious material, and without the blood coming into direct contact with the oxygen. The relatively large surface area of each membrane element 35 provides for maximum diffusion of oxygen through the layers 33a, b for introduction to the blood passing therethrough, and Iwithout any bubbling or gaseous mixtures adversely affecting the condition of the blood being circulated.

This apparatus can also be used as an artificial kidney simply by substituting layers of cellophane for the aforementioned polyethylene layers, and by using a dialyzing solution in place of lthe oxygen.

While this invention has been described with particular reference to the construction shown in the drawing, it is to be understood that such is not to be construed as imparting limitations upon the invention, which is best defined by the claims appended hereto.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

l. In an extracorporeal circulation system for oxygenat ing blood, a main uid flow control unit defining a first uid flow network and a second fluid ow network, membrane elements separating at least parts of said Huid iiow networks, said membrane elements accommodating gaseous ilow and excluding liquid ilow therethrough, means for circulating blood through said first uid flow network, and means forv circulating oxygen through said second fluid ilow network, said main uid flow control unit comprising a plurality of juxtaposed panels secured together in stacked relationship, each said panel including a section of said first iluid flow network, and communicating duct means linking all of said lirst fluid liow networks together, each one of said panels supporting one of said membrane elements in spaced apart relationship with adjacent membrane elements, the space between all adjacent membrane elements comprising segments of said second fluid flow network, and communicating duct means linking all of said segments of said second uid dow network together, each said membrane element comprising a pair of juxtaposed liquid-impervious and gas-transmitting sheets dening a liquid ow path therebetween, and marginal portions of each pair of said sheets being in communication with said first lluid ow duct means, a plurality of spot seals connecting together facing portions of said pair of sheets of each said membrane'element, in predetermined spaced-apart locations throughout the whole area of their confronting faces to restrain the sheets of each pair from separating apart, and said seals defining a tortuous path through the space between each pair of sheets constituting said membrane element, to form a thin hlm of blood passing through each pair of said sheets.

2. In an extracorporeal circulation system for oxygenating blood, a main fluid flow control unit defining a iirst iluid low network and a second fluid ow network, membrane elements separating at least parts of said duid flow networks, said membrane elements accommodating gaseous ow and excluding liquid ow therethrough, means for circulating blood through said iirst iluid flow network, and means for circulating oxygen through said second iluid how network, said main lluid ldow control unit cornprising a plurality or" juxtaposed panels secured together in stacked relationship, each said panel including a section of said first fluid flow network, and communicating duct means linking all of said iirst fluid flow networks together, each one of said panels supporting one of said membrane elements in spaced apart relationship with adjacent membrane elements, the space between all adjacent membrane elements comprising segments of said second fluid llow network, and communicating duct means linking all of said segments of said second iluid liow network together, each said membrane element comprising a pair of juxtaposed liquid-impervious and gas-transmitting sheets defining a liquid ilow path therebetween, and marginal portions of each pair of said sheets being in communication with said first uid flow duct means, a plurality of spot seals connecting together facing portions of said pair of sheets of each said membrane element, in predetermined spaced-apart locations throughout the whole area of their confronting faces to restrain the sheets of each pair from spreading apart, and said seals defining a tortuous path through the space between each pair of sheets constituting said membrane element, to form a thin lilm of blood passing through each pair of said sheets, each said panel further comprising a pair of substantially identical rectangular frames each having a pair of side strips and a pair of end strips and a central transverse cross-piece defining a pair of rectangular openings, the inner edges of said end strips defining a pair of transverse channels opening outwardly from one surface of said frame, the inner edges of said side strips and both edges of said cross-piece delining one set of longitudinal channels adjacent to each rectangular opening, said longitudinal channels opening outwardly from the opposite surface of said frame, each said panel having said opposite surface of one of the pair of frames facing said opposite surface of the other one of said pail' of frames, and said one surface of each frame of each said panel facing said one surface of the adjacent frame of the next adjacent panel.

3. An extracorporeal circulation system as set forth in claim 2, wherein one of said sheets is secured to said opposite surface of each said panel, and said paths through the space between each said membrane element communicate with said set of longitudinal channels adjacent to each rectangular opening, and said ducts extending through all or" said end strips and cross-pieces of said frames being in communication with said longitudinal channels.

4. An extracorporeal circulation system as set forth in claim 3, wherein said communicating duct means of said second fluid low network extends through said side strips of all of said frames in communication with said transverse channels.

References Cited in the tile of this patent UNITED STATES PATENTS 2,650,709 Rosenak et al. Sept. 1, 1953 2,686,154 MacNeill Aug. 10, 1954 2,799,644 Kollsman July 16, 1957 2,880,501 Metz Apr. 7, 1959 2,891,900 Kollsman June 23, 1959 OTHER REFERENCES Anthonisen et al.: Skeggs-Leonards Type of Artificial Kidney, The Lancet, pages 1277-1278, Dec. 22, 1956.

Kolt et al.: Cardiac Arrest, lournal of The American Medical Association, volume 164, No. 15, pages 1654-1655, Aug. 10, 1957. (Available in Scientic Library.)

Clowes et al.: An Artificial Lung Dependent upon Diiusion of Oxygen and Carbon Dioxide through Plastic Membranes, from Journal of Thoracic Surgery, vol. 32, No. 5, pp. 630637. 

